dragonfly/dragonfly.c

   1 /*      $OpenBSD: fmt_scaled.c,v 1.10 2009/06/20 15:00:04 martynas Exp $        */
   2
   3 /*
   4  * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * fmt_scaled: Format numbers scaled for human comprehension
  31  * scan_scaled: Scan numbers in this format.
  32  *
  33  * "Human-readable" output uses 4 digits max, and puts a unit suffix at
  34  * the end.  Makes output compact and easy-to-read esp. on huge disks.
  35  * Formatting code was originally in OpenBSD "df", converted to library routine.
  36  * Scanning code written for OpenBSD libutil.
  37  */
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <errno.h>
  42 #include <string.h>
  43 #include <ctype.h>
  44 #include <limits.h>
  45
  46 #include "util.h"
  47
  48 typedef enum {
  49         NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
  50 } unit_type;
  51
  52 /* These three arrays MUST be in sync!  XXX make a struct */
  53 static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
  54 static char scale_chars[] = "BKMGTPE";
  55 static long long scale_factors[] = {
  56         1LL,
  57         1024LL,
  58         1024LL*1024,
  59         1024LL*1024*1024,
  60         1024LL*1024*1024*1024,
  61         1024LL*1024*1024*1024*1024,
  62         1024LL*1024*1024*1024*1024*1024,
  63 };
  64 #define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
  65
  66 #define MAX_DIGITS (SCALE_LENGTH * 3)   /* XXX strlen(sprintf("%lld", -1)? */
  67
  68 /* Convert the given input string "scaled" into numeric in "result".
  69  * Return 0 on success, -1 and errno set on error.
  70  */
  71 int
  72 scan_scaled(char *scaled, long long *result)
  73 {
  74         char *p = scaled;
  75         int sign = 0;
  76         unsigned int i, ndigits = 0, fract_digits = 0;
  77         long long scale_fact = 1, whole = 0, fpart = 0;
  78
  79         /* Skip leading whitespace */
  80         while (isascii(*p) && isspace(*p))
  81                 ++p;
  82
  83         /* Then at most one leading + or - */
  84         while (*p == '-' || *p == '+') {
  85                 if (*p == '-') {
  86                         if (sign) {
  87                                 errno = EINVAL;
  88                                 return -1;
  89                         }
  90                         sign = -1;
  91                         ++p;
  92                 } else if (*p == '+') {
  93                         if (sign) {
  94                                 errno = EINVAL;
  95                                 return -1;
  96                         }
  97                         sign = +1;
  98                         ++p;
  99                 }
 100         }
 101
 102         /* Main loop: Scan digits, find decimal point, if present.
 103          * We don't allow exponentials, so no scientific notation
 104          * (but note that E for Exa might look like e to some!).
 105          * Advance 'p' to end, to get scale factor.
 106          */
 107         for (; isascii(*p) && (isdigit(*p) || *p=='.'); ++p) {
 108                 if (*p == '.') {
 109                         if (fract_digits > 0) { /* oops, more than one '.' */
 110                                 errno = EINVAL;
 111                                 return -1;
 112                         }
 113                         fract_digits = 1;
 114                         continue;
 115                 }
 116
 117                 i = (*p) - '0';                 /* whew! finally a digit we can use */
 118                 if (fract_digits > 0) {
 119                         if (fract_digits >= MAX_DIGITS-1)
 120                                 /* ignore extra fractional digits */
 121                                 continue;
 122                         fract_digits++;         /* for later scaling */
 123                         fpart *= 10;
 124                         fpart += i;
 125                 } else {                                /* normal digit */
 126                         if (++ndigits >= MAX_DIGITS) {
 127                                 errno = ERANGE;
 128                                 return -1;
 129                         }
 130                         whole *= 10;
 131                         whole += i;
 132                 }
 133         }
 134
 135         if (sign) {
 136                 whole *= sign;
 137                 fpart *= sign;
 138         }
 139
 140         /* If no scale factor given, we're done. fraction is discarded. */
 141         if (!*p) {
 142                 *result = whole;
 143                 return 0;
 144         }
 145
 146         /* Validate scale factor, and scale whole and fraction by it. */
 147         for (i = 0; i < SCALE_LENGTH; i++) {
 148
 149                 /* Are we there yet? */
 150                 if (*p == scale_chars[i] ||
 151                         *p == tolower(scale_chars[i])) {
 152
 153                         /* If it ends with alphanumerics after the scale char, bad. */
 154                         if (isalnum(*(p+1))) {
 155                                 errno = EINVAL;
 156                                 return -1;
 157                         }
 158                         scale_fact = scale_factors[i];
 159
 160                         /* scale whole part */
 161                         whole *= scale_fact;
 162
 163                         /* truncate fpart so it does't overflow.
 164                          * then scale fractional part.
 165                          */
 166                         while (fpart >= LLONG_MAX / scale_fact) {
 167                                 fpart /= 10;
 168                                 fract_digits--;
 169                         }
 170                         fpart *= scale_fact;
 171                         if (fract_digits > 0) {
 172                                 for (i = 0; i < fract_digits -1; i++)
 173                                         fpart /= 10;
 174                         }
 175                         whole += fpart;
 176                         *result = whole;
 177                         return 0;
 178                 }
 179         }
 180         errno = ERANGE;
 181         return -1;
 182 }
 183
 184 /* Format the given "number" into human-readable form in "result".
 185  * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
 186  * Return 0 on success, -1 and errno set if error.
 187  */
 188 int
 189 fmt_scaled(long long number, char *result)
 190 {
 191         long long abval, fract = 0;
 192         unsigned int i;
 193         unit_type unit = NONE;
 194
 195         abval = llabs(number);
 196
 197         /* Not every negative long long has a positive representation.
 198          * Also check for numbers that are just too darned big to format
 199          */
 200         if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
 201                 errno = ERANGE;
 202                 return -1;
 203         }
 204
 205         /* scale whole part; get unscaled fraction */
 206         for (i = 0; i < SCALE_LENGTH; i++) {
 207                 if (abval/1024 < scale_factors[i]) {
 208                         unit = units[i];
 209                         fract = (i == 0) ? 0 : abval % scale_factors[i];
 210                         number /= scale_factors[i];
 211                         if (i > 0)
 212                                 fract /= scale_factors[i - 1];
 213                         break;
 214                 }
 215         }
 216
 217         fract = (10 * fract + 512) / 1024;
 218         /* if the result would be >= 10, round main number */
 219         if (fract == 10) {
 220                 if (number >= 0)
 221                         number++;
 222                 else
 223                         number--;
 224                 fract = 0;
 225         }
 226
 227         if (number == 0)
 228                 strlcpy(result, "0B", FMT_SCALED_STRSIZE);
 229         else if (unit == NONE || number >= 100 || number <= -100) {
 230                 if (fract >= 5) {
 231                         if (number >= 0)
 232                                 number++;
 233                         else
 234                                 number--;
 235                 }
 236                 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
 237                         number, scale_chars[unit]);
 238         } else
 239                 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
 240                         number, fract, scale_chars[unit]);
 241
 242         return 0;
 243 }
 244